The drug belongs to the next-generation of hepatitis therapies called direct antivirals, which block the action of proteins essential for viral replication, in Zepatier's case NS3/4A and NS5A.

Approval was based on clinical trial data showing that sustained virologic response (SVR) 12 weeks after the completion of therapy was achieved in 96 percent (301/312) of chronic HCV GT1b-infected patients given MSD's therapy.

Chronic HCV infection, caused by a blood-borne virus, is a major public health concern affecting more than 170 million people globally, 15 million of whom are living in Europe. Of the six genotypes of chronic HCV infection, GT1 is the most common in Europe accounting for around 66 percent of cases.

"Given the complexities of chronic hepatitis C, it is critical to have a variety of effective treatment options to ensure diverse types of patients have the highest possible chance to achieve cure," said Professor Rafael Esteban, chief of the internal medicine and liver unit of the Hospital Universitario Val d'Hebron, Barcelona, Spain, and professor of medicine at the Universidad Autonoma de Barcelona.

"In clinical trials, Zepatier achieved high cure rates among a broad range of chronic hepatitis C patients with genotype 1 or 4 infection, from patients who are treatment-naïve to many of those whose chronic HCV infection has been historically difficult-to-treat, providing an important new option in the fight against this global public health epidemic."

The company said it expects to begin rolling out the product between the fourth quarter of 2016 and the first quarter of next year.